add nltk punkt resource (#7063)

api/Dockerfile

 COPY --from=packages ${VIRTUAL_ENV} ${VIRTUAL_ENV}
 ENV PATH="${VIRTUAL_ENV}/bin:${PATH}"
 
+# Download nltk data
+RUN python -c "import nltk; nltk.download('punkt')"
+
 # Copy source code
 COPY . /app/api/
 

api/core/rag/rerank/weight_rerank.py

             if 'score' in document.metadata:
                 query_vector_scores.append(document.metadata['score'])
             else:
-                content_vector = document.metadata['vector']
                 # transform to NumPy
                 vec1 = np.array(query_vector)
-                vec2 = np.array(document.metadata['vector'])
+                vec2 = np.array(document.vector)
 
                 # calculate dot product
                 dot_product = np.dot(vec1, vec2)